Telephone system



June 29, 1943. G. zAPF 2,322,992

TELEPHONE SYSTEM Filed July 3l. 1939 2 Sheets-'Sheet 2 no |v2 l was 77st i'P-f gum" 12p mi u w if;A 3 Awus tim e wm Jim u? 1 )vv-h2 -Ha2 "L /NvE/vToR.- GEORG ZAPF Patented June 29, 1943 TELEPHONE SYSTEM Georg Zapf, Berlin-Charlottenburg, Germany; vested in the Alien Property Custodian Application July .'31, 1939, Serial No. 291,617

Y In Germany August 16, 1938 11 Claims.

The present invention relates to a circuit arrangement for determining calling stations-in particular in systems which'are forwardly operating pre-selectors. v v

The determination of the calling station is important for example when so-called toll-tickets are automatically made out in the` central arrangement especially for the purpose of determining the fee, which give a permanent record of certain of the data for the connection (the number of the called station as well as the number of the calling station, time, duration of the connection and so on).

Central arrangements for determining calling subscribers stations vand transmitting signals corresponding to the individual digits of a call number are known.

The present invention relates to a central ar# rangement for use for a very large number of subscribers stations in which complications are avoided as far as possible and which increases the economic working of the installation in that each junction line is associated with `a number of line 'groups consisting of marking lines and of lines which mark the connection of different potentials and when the time occurs for-determining the calling junction the marking of the latter is obtained by determination of the marking line and the amount of the potential applied and this is converted with the aid of condensers into impulses. j More specifically,V the invention comprises equipment common to a large number of subscribers lines which is adapted to be temporarily asociated with each connection extended from said subscribers lines (or with at least certain types of connections, e. g. high Valued) for the purpose of determining theidentity of the calling line and transmitting a code corresponding to telephone number of said calling line.

According to` one feature of the invention, the identifying equipment is common to a plurality of switches accessible to all subscribers lines over preselectors, and is adapted to be associated individually with aA particular one ofsaid switches in response to` a signal received by the switch after said switch has extended the connection from the calling subscribers line.

According to another feature, the common equipment includes a switch having a plurality of wipers with a different potential connected to each Wiper. 'Ihe subscribers lines are arranged in levels in the bank of this switch, in such fashion that all lines whose telephone numbers provided with (c1. 179-7) have, say, th`esame last digit appear inv the same level. lWhenever the common equipment `is seized to identify acalling linethe switch is operated to nd that line and` impress upon it `the potential connected to the wiperserving the level in which the calling line is arranged. The poten-y tials connected to the different wipers of `said switch vary from `one another in substantially uniform steps, the highest numbered Alevel being characterizedby highest value of potential, and vice versa.

According to still another feature, the identifying equipment includes a condenser which is charged, over the connection extended from the calling line, by the potential impressed upon said line by the switch. 'The value of the charge placed upon the condenser depends upon the value o'f the potential impressed upon the calling line and hence is the same for al1 calling lines arranged in the same level of the switch. The condenser is then employed to control an impulse sender to transmit impulses dependent in number upon the extent to which said condenser was charged. f

These and other features of the invention will be more fully understood from the followingdetailed description, which should be considered in connection with the drawings, and also from the appended claims. I f

The drawings, Figs. 1 and 2, comprise a circuit diagram embodying the invention, The two figures should be placed side by side with Fig. 1 to the left of Fig. 2. Across the top of the two figures is shown diagrammatically a connection which extends from a subscriber` Tn over a `junction. AL, the pre-selector VW and the group selector GW.

The arrangement for marking the number of the calling subscriber and transmitting impulse trains corresponding to the individual digit number is shown briefly with` fthe call-number-determining arrangement in the lower, part of the figure beneath the dotted lines. Sincethe determinationV of the callingV subscriber. and the transmission of. the impulse trainsonly takes upa short time such an arrangement can be used to the maximum possible extent. If in the pres# ent case it is assumed that the determination and the recording ofthe number of call does not occur for all connections but only for certain category, for example Vfor high valued connections then a calling number vdetermining device caribe associated with a large number ofsubscribers stations. l l

According to the invention it is assumed that a determining arrangement is associated with 2000 subscribers.

The main components of this arrangement are as follows:

(l) Selectors DAW and DBW The selector DAW serves to mark the subscribers in the first thousands group, the selector DBW for marking those in the second thousands group. Both selectors are of the same con-` struction, they consist of a magnet DA or DB by which 11 wipers dal-dall or dbI--dbll are operated. The selectors are l100 point selectors, i. e. their wipers step over contact-l banks consisting of 100 contact positions. The contact bank over which the wipers dal-dal 0 of ther Yual to the subscribers in a definite manner so in fact contact is made with the testwiper on the pre-selector individual to a subscriber.. Thus the connection of the contact positionsis arranged so that the first contact of the wiper dal is connected with the subscriber H of the first hundred in the iirst thousand, i. e. with the subscriberwhose call number ends with the digits 1111. The rst contact ofthe wiperv dal is connected with the subscriber 12 of the iirst hundred in therst thousand, i. e. with the subscriber whosercall number has the last 4 digits 1112., The Wipers dadall are only indicated schematically in the drawing, the wiring .of their contacts Ato the individual subscribers following without any further consideration. The first contact of the wiper dal 0 of the selector DAW is connected with the subscriber whose call number has the four last digits 1110. Similarly in the selector DBW the subscriber in the second thousands 2T is marked. The rst contact of the wiper dbi is connected with a subscriber who-se call number ends in 2111, the` first contact; of the wiper db2 with a subscriber whose 4 last digits are 2112, and so on. Y

The second contact of the wiper dal is connected with-the subscriber 21 of the first hundred in the first thousand, i. e. with a subscriber whose call number ends with "1121, and the second contact of wiper daZ with a subscriber whose call number ends with 1122.

The eleventh contact of the wiper dal is connected with a subscriber 11 in the second hundreds in the first thousands, i. e. with a subscriber with the call number ending in 1211 while the corresponding contact of the wiper dbi is connected with a subscriber having a call number 2211. The eleventh -contacts of thewipers da2 and db2 are. connected with subscribers havingcall numbers ending with 1212 and"2212 etc. w

Thus the result is obtainedvthat'all the contacts over which the wipers daZ and db2 step are connected with subscribers whose callY number has"1 as the last digit, the contacts over the wipers da2 and db2 with subscribers having 2 as the last digit of their call number, theV contacts over which the wipers dall) and dblstep y been described in sufficient detail.

For the purpose of marking the call number the individualwipers now have differentiating criteria. Thus the wipers dal and dbi are extended to an unearthed battery of 6 volts, wipers ola2 and db2 to one of l2 volts, the wipers cia3- daS and db3-db9 to one of 18-54 volts, the wipers dal 0 and dbi() to one of 60 volts.

(2) Selector DWW This 'selector consisting of the magnet DW and the wipers dwl to dwd, serves for controlling. selectors DAW 'and DBW and for determining the call number of-the calling subscriber.

(3) Selector DMW This switch is operated by the magnet DM and has two wipers dml and dm2. It serves with the aid of a storage condenser and a thermionic tube to determine the last digit of the call number and to transmit impulses corresponding to its value to the registering arrangement.

(4) Selector DUW This is driven by the magnet DU and has four wipers lul-dud. It serves as an impulse sending control switch for transmitting impulse trains corresponding to the thousands, the hundreds and the tens digit of the call number.

(5) Saleeml DEW Three wipers of this selector are shown which are stepped on by the magnet DE. In the setting up of high valued rconnections it serves to receive a signal for initiating the registering of a calling number 'and to connect the call number determining arrangement to the connection path,

(6) Control switch of the 'magnet ST The feeding of the calling subscriber follows in` known manner over thel feeding bridge relays A and B in the selector: potential, winding'of relayA, wiper ai of the pre-selector VW, upper conductor of the junction line, subscribers loop, lower conductor of the junction line, wiper'b ofthe pre-selector VW, winding of the relay Bf potential. YOver the test wipercof the preselector the following circuit is completed: earth, battery, contacts not shown, winding of relay T, wiper c'of theV pre-selector, winding of relay C in the group selector GW, contact 42M: (mechanical contact opened as long as the group selector is off-normal) earth.V Inf addition to relay T inthe pre-selector 'whose function is not of importance attacca here and'therefore is not described, relay C in the group selectorv operates and closes its contact 4to; Operation of rel`ay Abover its winding-II does, however, not `take place since the relay is short-circnited byearth over contact Mc.

I B'y transmitting impulse trainsthe subscriber now sets up the connection inknown manner. In thel group selector relay Q is connected up over lower talking conductor, choke Dri` and contact abt This relay serves to receive the s ignalfor initiating registration of the call number ofthe calling subscriber. If, for example, after-'the' Setting-flip of one or more vswitching stages, a particular" position` is reached e.,g. theposition witl'i which a registering arrangement is asso# ciated l('r'ir'inting `or punchingdevice) then Afrom this position battery potentialis connected to the lower talking conductor The operationlof" relay Q` effects the connection f`thecall` number' determining arrangement so "that in v"the 'erribodi ment the registering ``f the callnumber is brought about during the setting up of the connection.' It is understood that the registering ofthe call number 'can also be undertaken at a different moment, e. Ig. the termination of 'a connection. Instead of the connection of relayQ the 'signal for initiating the registering can be performed ina different" `,manner for example in I dependenceon tI-ieposition f tli'egrop selector, on" the as` sumption, of course,` that the position off'the group selector has already been arranged to dif# ferentiate between the values of the connections.

rIn this case then, relayQ -is removed and contact Mq which starts the call number determining arrangement, is replaced by means of a bank contact which is closed by the positioning of the group `selector corresponding to a high valued connection.

` When contact 40q is closed and the call number determining arrangement is free the following circuit is completed: earth, contacts Mq, 39u63 resistance Wil, windiiigf of relay'A'n,` battery, earth. In this circuit relay An is operated and by closing its contact Shan completes the followf-` ing circui'tfor relayfR: earth, contacts 301m, V3 lo, winding-"of relay R, resistance Will,` battery', earth. At contact 21T the magnetDE'f'of the selector' DEW is energised lso that the wipersfdel to de3`are stepped on'to the next contact, -The magnet DE has "a contact'32d`e which is now closed 'so that the relay R. is restoredby means of the shortV circuitandthiis the contactf 2111 is opent-id'.` -After the release4 of contact 32de relay Rf'is'iag'ain energised and at contact 21'1 again energises `rnagnetDE.` "In this-manner the' wipers of'tlfie-s`e1ectr DEW'are stepped on 'until by Y meansof-awlper dez the group selector is reached mllwhich the relay Qisvoperated.4 The following circuit -is `then completed: earth, contacts Mq, S'Qabgab, winding I of relay Ab,- wiper" de2; contants 36e, aan wi'miings` r and 1I of relayy P, bat: terme" earth. In this circuit relay" Pfoperate's and f(ln thegroup selectoryrelay Ab." 'Relay'jP closes its contact pand thus completes af holdfe ingA 'circuit for itself giver` its winding 111;' "lay Ab eloses Contact Slab (make-before-*break contact)l solthatlfor the duration-of the'y registering' ofthe cal number the following" circuit remains lg'fsedf` earth; resistanceY Wi|5`, Contact31111),` windin "Il of-rrelayA, wiper deze, contacts 36e, 34p,winc`l1rif"v `I'I. o'fi relayP;-battery,'earth.' Relay Aialso opens its contact `39a?) "and thus removes the "starting earth from relay A11. H By the "opening ofcontact )M712 furtheroper'aftion" of rela'yRi and thus fui-'ther operation: of. the magnet '-DlET-by4 means' of ero the contact 211` is prevented. The selector DEW thus remains' in the position over which it has found the group selector GW. y

After the opening of mechanical contact "kk the earthpotential is maintained on the e-conductor over contacts llc and 43ab. After the opening of contact 43ab earth potential is connected over contact Hc and winding II ofrelay' Ab. -Re1ay Ab remains energised in thisY circuit for the duration of the connection. h By the closing of Contact 29p relay'V is fene` gisedslwly due to the resistance connected in parallel withitsf winding and at Contact 3io a furtherV point is openedin the circuit for relay R. Before theo'peration of relay Vthe following'circuit is completed `for both" magnets `DA and DB of the selector DAW and DBW: earth, ccntact-3v,,2p, magnetshDA and DB, battery, earth; The wipers'dalf-dall and dbI-dbll are thusstepped on to the next contact. `The magnet'DA has a'contact 4da'which in operating energises` relay K. Bymeans'of contact 5k the following circuit is completed: earth, contact 5k', wiperV i103 Vin the rest posi-tion, winding of relay ALibattery, earth. Relay A2 closes contact Maz an'd thus the following circuit: earth,` battery, magnet DW of the selectcrvDWW, contacts I2um, |4a2, `Winding Iofrelay U, contact I3u,v earth. The magnet DW steps the wipers dwl to dw! on to contact `I, and wiper dal isfconnected up over wiper dwl. It is now determined b'y wiper dw l whether the wiper dal rests on the contact whichisconnected with wiper c of the preselector of the callingsubscriber. Assume that this is not the case.` Then after the operation of relay U in the above-mentioned circuit thecontacts 13u, 15u, 2lu, Illu and` 24u are opened and the con-- tacts V20u and 18u closed.V Contact l 1u is only openedwhen-relay U operates over both windings, i. e. when contact |3u is opened. Thus the resultis obtained that contact |111,` is only operated after the closing of` contacts I8u and 20w. By means of the latter contacts the storage condenser CI is connected to' earth and to the grid of the thermionicvalve. Since the condenser CI has no charge no switching is brought about by the operation of this contact. The therinlonric valve REI is arranged so that when battery potentialis applied to the grid over Contact Iluand `resistance Wil-2', relay H in the anode circuitcannot operate. If, however, there isA no battery 'potential applied lrelay H operates. Since in this case the storage condenser CI is to be witliout charge relayH isV energised after the ,i opening of contact'l'l. It opens its contact 6h N112,V On its release relay Uv again connects batf' i te'ry potentiaiaf.- @maar nu to alegriaV crine thermionicvalve-REI wherebythe release of re# lay'I-Ihl's eiectedgf'At contact 6h relay A2is "again'energisfed and overcontact No2 the mag- ,net DW (its "wiperrsthe'r'efore reach the second ciontaci and relayUj are energised. Thev storage condenser ,CI is again connected tothe gridof the valve'l REI while'v battery potential over resistance Wllfzfis"disconnected from the grid of tllv'e- ,A V In this v'n'ranner the wipers dwldtb4 -a're stepped on over their contactv banks. Thus the wiper' dwl tests, on stepping; over the rst 10 contacts, whether one of the wipers dai-dall) rests onthe contact towhich the calling `subscriber is connected and,A on stepping overthe contacts Il to 20, whether one of -the wipers dbl--dbl rests on the Contact to whichlthe calling subscriber is connected. When the wipers of the selector DWW reach the lastl contact 25 then over the wiper `dw2 in position 25 both magnets DA yand DB of the. twovselectors are energised. The wipers of these two selectors are thenstepped on to the next-contact.V A t contact lldarelay K is again energised and at contact k relayAZenergises, Whichbyclosing contact |4a2 eiects the second rotation of the Iselector DWW. By means of the ,Wiper dwlA it is now determined whether one of thewipers delta-dall) anddbldbi!) is connected tothe .calling subscriber and which of these contacts it is.v Y l Assume that-the` last four digits of Athe number ofthe 4calling subscriber are the digits 1161. The wiper c of the preselector of the calling subscriber This thus extended to the sixth contact of the contact bank associated with wiperdal. Azfter the wipers of the selectors DAW and DBW are connected to the sixth contact the selector DWW begins itsrotation and reachescontact I so that the storage condenser Cl receives a charge by means of thebattery potential of 6 Volts connected to the wiper dati.v The charging circuit forthe condensenCl is as follows: battery' povtential of 6 volts, wiper dal, contact 6, marking line 61, wiper c of the preselector,l wiper del of the selector-DEWcontacts 35p, 24u, |911., condenser CI, contacts 2Iu, l5u, wiperdw'l, contact l, battery` potential of 6` volts. In parallel with the condenser Cl a iurtherstorage condenser C2 is connected over contacts 22am and 25am'.y This condenser in addition to the condenser Cl vis charged v.by means of the battery potential of 6 volts -onthewiperV dati.` The charging period is determined by the delay with whichthe relay, U operates after the closing oi yContact YMaZr (brought about/ bythe shortcircuit of winding II-y at y contact 13u). The connection 0f the charged condenser CI to .the gridof the ther-v mionic Valve REl effective, sothat after the opening of ycontact-ilu and disconnection of the battery potentialr connected over the resistance Wil2 the Vrelay H in the an-odebonnection rel mains inthe normal position. Thus the relay A2 is maintained energised for some time over: earth, battery, winding of relay A2, Wiperv dm3 in the operated position, contact 6h, earth andthe selector DWW .remains at rest. f v f After the setting of the'selector DEW and on the operationof Yrelay 1P, at contact 8p the following circuit' is completedI for relay Ul earth, battery, resistance vWilli, contact 8p, resistance Wil3, winding, of relay UI, earth. As previously mentioned relay'A2 kis operated intermittently and thus the stepping on of the selector DWW isr effected.- By means of contact 1va2 a circuit is completed f or. shortcircuiting re1ay U I.' .The short. operatingperiod of relay A2. duringfthe stepping ,of the selector DWWisnOtsiFEicient however to restoreurelay':U A after the test l ing of the calling subscriber byfrneans -the selector DWW,lrelay A2 remains energised for some time, then contact 1a2 also remains closedY for sometime and the release ofi relaylUl is brought about. 'Ihe following circuit isf'then completed: earth, battery, resistance Wi'l8, fc'ontactsjp, Het,y limi, winding of .relay Um, earth.

In` this circuit relay Um operates and closes the followingholding circuit for itself: earth, battery, resistance Wz'l, contacts 8p, Sum, winding of relay Um, earth. Relay Um by opening contact Hmm disconnects relay H. By the opening of contact I2um the circuit for the magnet DW and relay U is interrupted. By the closing of contacts 2611.111. and 23am the storage condenser C2 charged with 6 volts is connected on one hand to the wiper dml of the selector DMW and on the other hand to the grid of the valve REZ.

There follows in the rst place a determination o f the thousand digit andv transmission oi correspondingimpulses over the lower talking con-f ductor to axsucceeding registering arrangement (printing or punching device). vBy the closing of contact 65nm the following circuit is com,- pleted: earth, control switch contactlst (closed in positions 1 .to 3 of the control switch), wiper 'dtuiuin the rest position, contacts 65nm, 64713, 62e, Bibl, Winding of relay Al, battery, earth. In this circuit relayv Ai operates and its operation is delayed since parallel to its winding over contact 60k! a damping resistance Wz'l6 is connected. By the closingV of contact 41a! the rstimpulse transmitted over the lower line to the registering device as follows: earth, contacts 46lcl, Mal, 48am, wiper 1163 contact 4l5ab, choke Dri, lower talking conductor, wiperv b of the group selectors and further to the registering arrangement in a subsequent connecting stage. By the closing of contact ldl the following circuit is completed for relay Vlz earth, contacts, 50h2, 5Ial, winding of relay VI, battery, earth. Relay VI operj ates in this vcircuit and at contact 52'vl energisesV the relay Wl. By the closing of contact 58al, relay BI is energised slowly since parallel to its winding over contact 5916i a damping resistance Will is connected. By the opening of contact Elbi the circuit for relay Al is interrupted'so that by the opening of Contact 58a| the circuit for relay Bl is interrupted. At Contact Blbj the circuit for relay Al is again completed. Relays Al `and BI therefore form an interrupting arrangement which by means ofjcontact 41a! transmits impulses over the lower talking conductor to the registering -arrangement and simultaneously by means' of contact 5617i the relay `BI transmits impulses to the magnet DU over: earth, contact 5 6bl, `control switch contact 58st (closed in positions VI-3) magnet DU, battery, earth.

The wiper dwl over. contact I and wiper 4dal has found the callingsubscriber. The Wiper 11114 thus rests on Contact segment ,|--|0. `If 4the wipers of the sender control switch DUW reach the first contact after the iirst operationof magnet DU by means o facontact 5619i ythen the following circuit is completed: earth, wiper duid, contact segment` |-i0, wiper dui on .contact-l control switch contactlst (closed in the control switch position l) lwinding of relay 1 -I2, battery, earth. @In this circuit relay H2 operates and by clcsing its. contact y 49M energises relay K I over thewinding I. Relay Kl opens its contact 46k| and thusprevents the further transmissiomof impulseswby means of contact Mal over the lower talking conductor. Relay KI also closes a hold- .circuit for itself over contact 53klgas follows:

earth, lcontacts 5212i, 537c|, winding II ofrelay n relay H2 is restored. `Contact 50M is closed and the circuit for relay V I is further maintained. 'Ihis relay, due to its slow release, has not during the short opening of contact 50h2 the opportunity of restoring. During the short interruptions at contact IaI during the interaction between the relays AI and BI, relay VI cannot restore. Relay H3 closes its contact 55h3 and short circuits its winding II whereby the release of the relay is delayed. By the opening of contacts 59M and Slcl the slow to release feature for relays AI and BI is removed so that their interaction is carried on more rapidly during the time in which impulses are not transmitted over the lower talking conductor and the selector DU is rapidly restored to normal.

-When wiper du4 has reached its normal position the circuit for relay AI is interrupted for some time (contact 64h3 open). Due to the long opening of contact 5Ia| relay VI has the opportunityl of restoring. On the opening of contact 52vI relays WI, KI and H3 restore. During the release period for relay H3, the following circuit is completed for relay X: earth control switch contact GEST (closed in the position I-3) wiper du4 in the rest position, contacts 65am, 63h3, 69wl, winding of relay X, resistance Wi, battery, earth. 4At. contact 10:13, relay X locks up. By the closing of contact 66a: the Acontrol switch magnet ST is `energised and the control `switch is `then brought to position 2; By the closing of contact 'lIst relay'iX is restored by the short circuit and thus opens contact x. Meanwhile relay H3 has restoredand closed contact 64h3. There follows they further connection of the impulse relay AI over ythe 'following path: earth, control switch contact 66st (closed in positions I--3), wiper du4 Vinfth'enormal position, contacts 65am, 64h3, 62e, .6IbI, winding of relay AI, battery, earth. At contact 58a| the relayBI is again connected: and

`the interaction of the two relays begins again.

When wiper du4 movesolf-normal the circuit for relay Al extends over the contact segment short circuiting contacts 65am and 64713. The relays AI vand BI bring about a further operation of the selector DUW. By the closing of contacts 59M `*and* 'Ellkl both relays are rendered slow-to-re- Vlease so that the impulse transmission of the reg'- isteringarrangement continues over the talking conductors at the :required speed.

`In this operation of the selector DUW impulses l:are transmitted in accordance with the hundreds digit'` of the call number. The hundreds digit is transmitted bythe position of the wipers of the selectors DAW. and DBW. When these wipers rest on contacts I to I0 the signal transmitted in'- dicated that that call number is in the rst hundred. When thev wipers rest on the contacts I I-;20 the signal indicates that the number of the calling subscriber is inthe second hundred and so on. Since the position of the two selectors DAW and DBW is the same it is suf- 1-flcient tomark the hundreds digit over one wiper of` cme of the two selectors. In the embodiment this; is performed by the wiper dal I of the selector DAW; Since the calling subscriber is assumed to lie in the rst hundred the wiper dal I' of the selector DAW rests on contact segments I -I0. When under 'the action of the relay interrupter thewipers-duI-du4 of the sender control switch are in the rst position, and by the closing jot,` contact 4'Ial` an impulse is transmitted over the lower talking conductor, to the registering arrangement and consequently the following circuit is completed: earth, wiperdall, contact segment I-I 0, wiper duZ on contact I, control switch con-tact 16st (closed in the control switch position 2), winding of relay H2, battery, earth. Relay H2 operates in this circuit and at contact 49h2 energises relay KI which by the opening of Contact 4IIcI prevents any further impulse transmission to the registering arrangement. Operations now occur which are necessary for the transmission of impulses for the tens digit. If the selector DU has completed its operation then in the manner described, by means of relay X the control switch is brought to position 3. Thus over the control switch contact 'I'Ist the wiper du3 of the sender -control switch DUW is connected which now serves to determine the tens digit of the wiper.

The tens digit of the call number is determined by the position of the wipers of the selectors DAW and DBW withinV the individual contact groups for marking the hundreds digit. The contact bank of the wiper @Zbl I of the selector DBW is so arranged that all contacts with the iirst digit l are connected together (i. econtacts I, I I, 2l, and so on) and are extended to contact I of the contact bank steppedover by the wiper cia3. AI contacts with the units digit "2 (i. e. contacts 2, I2, 22, etc.) are extended to the contact 2 of the contact bankof the wiper du3 and so on.

In the present embodiment, the wipers ofthe selector DAW and DBW are stopped on thesixth contact of the first hundred. Contact dbII thus rests .on contact 6, and is connected` to contact E oi the contact bank of the wiper cia3. On the next operation of the selector DUW by means of contact 4IaI these impulses are transmitted over the lower talking .conductor tothe succeeding registering arrangement. When this has taken place the following circuit is completed for relay H2: earth, wiper dbi I on 4contact 6, wiper du3 on contact 6, control switch contact'I'Ist (closed in position 3), winding of relay H2, battery, earth. Relay H2 with the aid of relay KI terminates the transmission of further impulses to the registering arrangement.: When the sender control switch DUW has completed its rotation, then in the manner described, by means of relayX the stepping on of the control switch to the next p0- sition- (i. e; position 4) takes place. After the release of relay H3 in the manner described the following circuit. is completed: earth, control rswitch contact` 61st (closed in position 4 of the longer controlled by contact 56-b| but the selector` DMW instead whose magnet DM receives impulses over the following path: earth, contact 56bl, control switch contact 51st (closed in position 4 of the ycontrol switch), magnet DM, bat,- tery, earth. After the stepping on of the wiper dml to the normal position the circuit for relay AI extends over the contact segment of wiper dmZ, contacts 62e and I-Ibl short circuiting the wiper du4 and contacts 65am and 64h3. The selector DMW makes` one complete rotation.

The` Wiper dml steps over l0 contacts which are connected with the individual potential stages of a potential divider constructed of resistances Wil--WiIlL As mentioned previously over contact 23am wiper dmI is connected with the stortial of 6 volts applied to the valve while over contact 26am the condenser is extended to the grid von the new connecting stage.

6 i of the thermionic valve REZ. The condenser C2 ac'ts 'as battery potential of 6 volts. Therefore over` wiper dml in the zero position there is con.- nected to the grid of the valve REZv a potential of 60|6=66 volts compared with 60 volts of the cathode of the valve, i. e. the bias compared with 'the cathode is 6 volts negative. This negative bias onthe grid cuts off the anode current so that relay Hl which is connected with earth over contact 28am cannot operate. If the wiper dml had reached the nrst contact after the first operation of magnet DM by means of contact 56M which contact is connected to a potential of 54 volts then a potential of 54+6=60 volts is connected to the grid of the valve, i. e. the grid potential no longer :exceeds the cathode voltage which is'60 volts. Relay HI thus operates, since the grid no longer cut off anode current. By means of contact Mal an impulse is transmitted over the lower talking conductor to the registering arrangement. Relay HI closes its contact 54M and thus over contact 52ml and earth a circuit is completed for relays KI and H3. Relay KI by opening its contact 46k! prevents further impulse transmission to the registering device. The further stepping on of the wipers of the selector DMW is thus without effect on the registering arrangement. If the wipers of the selector DMW have reached their normal position the following circuit is completed for relay X: earth, control switch 61st (closed in position 4 of the control switch) wipers dmZ and dud in the normal position, contacts 65nm, 63h3, 69ml, winding of Arelay X, resistance Wi, battery, earth. By the closing of contact 68:1: thecontrol switch is stepped on to position 5.

vThe following circuit is completed: earth, control switch contact 12st (closed in position 5 of the control switch), Winding of the relay E, battery, earth. Relay E locks up in the following circuit: earth, contacts 14o, 13e, winding of relay E, battery, earth.

Relay E brings about the release of the arrangement shown. By the opening of contact 36e relay P is restored, This opens the circuit for relay V at contact 29p. By the closing of contact 3io relay R is connected to the contact 30cm so that when the contact corresponding to contact 40g of another connecting stage is closed after the completion of the circuit at the closing of contact 301m, the selector DEW is set By the opening of contact 8p the holding circuit for relay Um is interrupted so that over contact 12mm the 'magnet DW and the relay U operate, and by the opening of contact 11u, relay H connected by contact lum in the anode of the thermionic valve is operated. By the opening of contact 6h relay A2 is restored and relay U is disconnected at contact l4a2. By the closing of contact Hu relay H is again disconnected and relay A2 connected. In this Way the magnet DW of the switch DWW receives impulse until its wipers have been restored to normal.

If the storage condenser is charged with another value, for example 18 volts connected over the Wiper dai! to 11113v the wiper dml must execute three steps, i. e. it must be set on the potential stage of 42 volts until the anode current is no longer shut off by the grid. Thus in this case in order to mark the units digit of the call number 3 impulses are transmitted over the lower talking conductors to the registering device.

I claimz' l 1. In a telephonev or like system, groups 'of subscribers lines, identifying equipment common to said lines, means in said equipment for producing electrical potentials of different values, each value corresponding to a different one of said groups of lines, means operated to extend a connection from any calling one of said lines, means in said equipment then operated to nd said calling line and to impress upon it a particular potential of a value corresponding to the group of which said calling line is one, and means controlled, over the connection extended from the calling line, by the potential impressed upon saidv calling line to transmit a variable impulse code depending upon the value of said potential.

2. In a telephone orv like system, a plurality of groups of lines, identifying equipment common to said lines, means in said equipment for producing electrical potentials of different values, each value corresponding to a different one of said gro-ups of lines, means common to rsaid lines operated to extend a connection over any one of said lines, means operated after said connection has been extended for then associating said iden# tiiying equipment individually with said one line, vand means in said equipment controlled by said last means to impress upon said one line a particular potential of the value corresponding to I the group of which said line is one. i

3. In a telephone or like system, a plurality Vof subscribers lines, means for extending a call from any oney of said lines, means common to said lines for identifying the vcalling line, said last means including a switchhaving said lines arranged in levels in its contact bank, means for operating said switch to find the -calling line and to impress upon saidV line a potential depending in value upon the contact bank level in which said. line is found, and. means controlled by the value of said potential impressed upon said line to transmit an impulse code corresponding to the4 level in which said calling line is found.

'-4. In Va telephone or like system, a plurality of subscribers lines, a plurality of switches common to said lines, means for extending a connection from any callin-g one of said lines to any one of said switches, means then effectiveto apply a different potential to each of said subscribers lines at the same time, discriminating means associated with said one switch and controlled over the connection extended thereto from said calling line by the particular one of said potentials applied to said calling line, and means controlled by said rdiscriminating means `for transmitting an impulse code indicative of said potential applied to said calling line.

5. In a telephone or'like system, two lines, means common to said lines for extending calls over either of said lines, means for characterizing one of said lines by a potential of one value if a call is extended over that line and for characterizing the other of said lines by `a potential of a different value if a call is extended over said other line, and means common to said lines effective after said rst means has extended a call over either of said lines to determine the identity of the line over which said can 'is extended from the value of the potential characterizing that line.

6. In a telephone or like system, a plurality of 'lines each having a potential of a diierent value associated therewith, means for extending calls over any of said lines, andmeans common to said lines controlled by the extending of a call over one of said lines to transmit a variable impulse code dependent upon the value of said potential associated with saidl one line, thereby to identify the line over which said call was extended.

7. In a telephone or like system, a plurality of lines, a different source of potential associated with each of said lines, a condenser common to said lines, means for extending calls over any of said lines, means operated to charge said condenser from the source associated with a par-l ticular line when a call is extended over that line, said condenser charged differently from the different sources and thereby effective to register the identity of the line over which the call is I' extended.

8. In a telephone or like system, a plurality of subscribers stations, a condenser common to said stations, means for extending a call from any of said stations, means common to said stations operated to determine which of said stations is the calling station, and means controlled by said last means to charge said condenser to a variable potential depending upon which station is the calling station.

9. In a telephone or like system, a plurality of lines, a condenser common to said lines, means for extending a call over any of said lines, means common to said lines operated to determine which of said lines said call is extended over, and means controlled by said last means to charge said condenser to a value depending 11P- on which of said lines said call is extended over.

10. In a telephone or like system, a plurality of lines, a condenser common to said lines, means for extending a call over any of said lines, and means operated after said call has been extended to place upon said condenser a charge automatically depending in value upon which line said call was extended over.

11. In combination, a plurality of lines, a condenser common to said lines, means for marking any of said lines to distinguish that line from the other lines, means then operated to determine which of the lines is marked, and means controlled by said last means for charging said condenser to a value depending upon which line is marked.

GEORG ZAPF. 

